THE ACCURACY OF A LEAD QUESTIONNAIRE IN PREDICTING ELEVATED PEDIATRICBLOOD LEAD LEVELS

Objectives: To determine the prevalence of elevated blood lead levels and to evaluate the accuracy of a lead screening questionnaire in a we stern United States urban inner-city pediatric population. Design: A c onvenience sample of children between the ages of 6 months and 6 years seen for a well-child visit were enrolled. Venous blood lead levels w ere measured and a lead screening questionnaire was completed. Setting : The primary care clinics of the 10 community health centers of the c ity and county of Denver, Colorado. Approximately 85% of children rece iving services are below the 150% poverty level and 54% are insured th rough the state's Medicaid program. Subjects: A total of 2978 children seen for a well-child visit from February 1993 to January 1994. Mule Outcome Measures: The prevalence of elevated blood lead levels and the operating characteristics of both the Centers for Disease Control and Prevention lead screening questionnaire and the complete questionnair e used in Denver, using venous blood lead levels as the criterion stan dard. Results: The mean blood lead level was 0.20 mu mol/L (4.19 mu g/ dL). Eighty-five children had blood lead levels of 0.48 mu mol/L (10 m u g/dL), representing 2.9% of the study group (95% confidence interval [CI], 2.3-3.5). Only 0.3% of the cohort had blood lead levels greater than 0.96 mu mol/L (20 mu g/dL). The sensitivity, specificity, and po sitive predictive value of the Centers for Disease Control and Prevent ion questionnaire was 57%, 51%, and 3%, respectively. The sensitivity, specificity, and positive predictive value of the complete questionna ire was 59.7%, 36%, and 2.6%, respectively. The marginal cost of ident ifying a child with a blood lead level greater than 0.96 mu mol/L (20 mu g/dL) was $4925. Conclusions: Few of the low-income children in thi s study had blood lead levels greater than 0.48 mu mol/L (10 mu g/dl). The questionnaire did little better than chance at predicting the pre sence or absence of elevated blood lead levels and cannot replace a bl ood lead level test for childhood lead screening in this community.